Gear train arrangements

ABSTRACT

Gear train arrangements for transmitting a power from a driving source to a driven member at more than three speeds in one direction and another speed in the opposite direction, the gear train arrangements using basically three planetary gear sets and at least five friction elements such as clutches and brakes which are selectively actuated to selectively engage the rotary members of the three planetary gear sets to deliver an output power at the above said speeds. The gear train arrangements are specifically adapted for use in an automatic transmission system of a motor vehicle using a torque converter or fluid coupling.

United States Patent [191 I Mori et al.

[ GEAR TRA-IN ARRANGEMENTS [75] Inventors: Yoichi Mori, Yokohama; Nobuo Okazaki, Chigasaki; Kunio Ohtsuka; Tetsuya Iijima, both of Tokyo, all of Japan [73] Assignee: Nissan Motor Company, Limited,

Yokohama, Japan 22 Filed: Sept. 13, 1972 211 Appl. No.: 288,548

Related US. Application Data [62] Division of Ser. No. 30,496, April 21-, 1970, Pat. No.

[30] Foreign Application Priority Data Dec. 10, 1974 2,919,606 1/1960 Karlsson et al. 74/759 X [5 7] ABSTRACT Gear train arrangements for transmitting a power from a driving source to a driven member at more than three speeds in one direction and another speed in the opposite direction, the gear train arrangements using basically three planetary gear sets and at least five friction elements such as clutches and brakes which are selectively actuated to selectively engage the rotary members of the three planetary gear sets to deliver an output power at the above said speeds. The gear train arrangements are specifically adapted for use in an automatic transmission system of a motor vehicle using a torque converter or fluid coupling 1 Claim, 37 Drawing Figures Pmgmennu: 10 mm 3,853; 023

saw on or 15 PATIENTEUBEMO 1914 3853x323 SHEET 0E 0F 15 OUTPUT INPUT PATENTEDBEB 101974 3853023 sum 08 or 15 INPUT (F) OUTPUT INPU'HR) -man use 10 1914 3353.023

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lNFUT(F) OUTPUT PATENTEU on: 10 1914 $853323 sum 1a or 15 F/g/3a OUTPUT L 1 L W N 1 R| Cr SI GEAR TRAIN ARRANGEMENTS This is a division, of application Ser. No. 30,496 now US. Pat. No. 3,701,293 filed April 21, 1970.

It relates to gear train arrangements for a transmission system of a motor vehicle and, more particularly, to gear train arrangements of planetary gear type adapted to provide basically four forward and one reverse vehicle speeds.

A usual gear train arrangement using a planetary gear system is made up of a combination of one or more, similar or different, planetary gear sets each having one or more planet pinions and is operated through actuation of friction elements such as clutches and brakes which are arranged to attain a desired combination of gear ratios. Typical of such gear train arrangement is the one that uses three simple planetary gear sets which are combined together to provide three forward and one reverse vehicle speeds. (It may be noted that the term simple planetary gear set as herein used is intended to refer to a planetary gear set having a single planet pinion.)

Foremost of the practical requirements of a gear train arrangement to attain an increased number of vehicle speeds is a wide selection of the combinations of gear ratios, which requirement, however, is reflected by an increased number of component parts of the gear train arrangement and complicated gear shifting operations.

In order that the gear train be snugly accommodated within a limited space in the transmission system, every component of the planetary gear system should be as small in dimensions as possible. From the view point of production economy, moreover, it is desired that the number of the component parts of the gear train be reduced to a minimum and that the parts corresponding in function be fabricated to be common in geometry to one another so as to permit of quantity production. Another important requirement of the gear train of a transmission system is the ease of gear shifting operations.

It is, therefore, an object of the invention to provide gear trainarrangements adapted to provide basically four forward and one reverse vehicle speeds.

Another object is to provide gear train arrangements providing essentially four forward and one reverse vehicle speeds with wide selection of the combinations of gear ratios.

Still another object is to provide gear train arrangements providing four, or even more, forward and one reverse vehicle speeds, which arrangements are constructed with a practically minimum number of component parts and nevertheless can provide practically any desired combination of gear ratios.

Still another object is to provide gear train arrangements that are suited for quantity production.

Still another object is to provide gear train arrangements providing four, or even more, forward and one reverse vehicle speeds with utmost ease of gear shifting operations.

In order to achieve these and other objects, the invention proposes to use various combinations of basically three substantially identically sized planetary gear sets which are operated by means of two or three clutches and two or three brakes. The gear train arrangements using such combinations can be readily modified with incorporation of additional minor arrangements into those providing five or six forward and one reverse vehicle speeds. In the drawings:

FIGS. 1 to 8 are sectional views schematically showing various preferred embodiments of the invention, each of which embodiments uses three planetary gear sets with two clutches and three brakes to provide four forward and one reverse vehicle speeds;

FIG. 9 is similar to FIGS. 1 to 8 but shows other embodiment using three planetary gear sets with three clutches and two brakes to provide four forward and one reverse vehicle speeds;

FIGS. 10, It and 12 are views illustrating still other embodiments using three planetary gear sets with three clutches and three brakes to provide four forward and one reverse vehicle speeds;

FIG. 13 is a view illustrating still another embodiment using three planetary gear sets with three clutches and three brakes to provide five forward and one reverse vehicle speeds;

FIG. 14- is a view illustrating still another embodiment using four (including one auxiliary) planetary gear sets with three clutches and four brakes to provide four forward and one reverse vehicle speeds;

FIG. 15 is a view illustrating still another embodiment using four (including one auxiliary) planetary gear sets with two clutches and three brakes to provide five forward and one reverse vehicle speeds;

FIG. 16 is a view illustrating still another embodiment using four (including one auxiliary) planetary gear sets with three clutches and four brakes to provide six forward and one reverse vehicle speeds;

FIG. 17 is a view illustrating still another embodiment using four planetary gear sets with three clutches and five brakes to provide an overdrive from the fourth speed;

FIGS. 1a to 16a are diagrams each showing the different revolution speeds of the individual rotary members of the planetary gear sets used in the embodiment illustrated in the corresponding figure out of FIGS. 1 to 16; and

FIGS. lb, 4b, 6b, 7b, 8b, 9b and 10b are views each showing a modification of the embodiment illustrated in the corresponding figure without the subscript.

Corresponding reference numerals and characters represent like members in all the figures.

It may be noted in regard to the drawings that only the upper half of each gear train arrangement is herein shown for simplicity of illustration because the gear train arrangement is generally symmetrical with respect to the input and output shafts.

First referring to FIG. 1, the gear train according to one embodiment of the invention is, as customary, connected at one end with an engine through an input shaft 10 and a torque converter or fluid coupling (not shown) and at the other end with a differential (not shown) through an output shaft 11 of the transmission system. I

The gear train as shown includes a first, second and third planetary gear sets I2, 13 and 14, all of which are constructed as simple planetary gear sets which are fabricated to be substantially identical in geometry with each other.

The first planetary gear set 12 comprises an outer ring gear R a planet pinion P, meshing with the outer ring gear, and a sun gear S meshing with the planet pinion. The second planetary gear set 13 similarly comprises an outer ring gear R a planet pinion P meshing with the ring gear, and a sun gear S meshing with the planet pinion. The third planetary gear set 14 also similarly comprises an outer ring gear R a planet pinion 1 meshing with the ring gear, and a sun gear 8;; meshing with the planet pinion. The planet pinions P P and P are carried on and revolved by pinion carriers 15, 16 and 17, respectively. The ring gears, pinion carriers and sun gears are all rotatable about a common axis which is in line with the axes of the pinion carriers. More detailed discussion on the constructions and motions of the planetary gear set per se is herein omitted because they are well known in the art.

The ring gear R, of the first planetary gear set 12 is constantly connected to and rotatable with the planet pinion P of the second planetary gear set 13 through the pinion carrier which forms part of a drum 18. The sun gears S and S of the first and second planetary gear sets 12 and 13, respectively, are constantly connected to and rotatable with the input shaft of the transmission through mechanical linkages 19 and 20, respectively. The ring gear R is constantly connected to and rotatable with the sun gear 5;, of the third planetary gear set 14 through a drum 21. The pinion carrier 17 is constantly connected to and rotatable with the output .shaft 11 of the transmission to carry an output power to the differential (not shown).

The pinion carrier of the planet pinion P is connected to a first band brake B, which, when applied, holds the pinion carrier 15 stationary. The drum 18 interconnecting the ring gear R and pinion carrier 16 coacts with a second band brake B which, when applied, holds both the ring gear R and pinion carrier 16 stationary. The drum 21 interconnecting the ring gear R and sun gear 8;, coacts with a third band brake B which, when applied, holds both the ring gear R and sun gear 8;, stationary.

Two clutches C and C are provided to selectively connect the ring gear R to the drum 21 and the input shaft 10, respectively.

Now, it is well known in the art that, assuming the revolution speeds of a ring gear, sun gear and pinion carrier of a given planetary gear set are Nr, Ns and Np,

' respectively, and the ratio of the number of teeth of the sun gear to the number of teeth of the ring gear is a, then the following equation holds:

(a+l)-Np=Nr+a-Ns I Thus, for the planetary gear sets 12, 13 and 14, the following equations can be derived:

where the subscripts ll, 2 and 3 represent the first, second and third planetary gear sets 12, 13 and 14, respectively.

In consideration of the constant connections between some of the rotary members of the planetary gear sets, the following equations hold:

The speeds Ns and Np are equal to the revolution speeds of the input and output shafts 10 and 11, respectively.

These mathematical relations between the revolution speeds of the individual rotary members of the planetary gear sets can be graphically illustrated in FIG. 1a, wherein points L, M and N are given on a line 0-0 in such a manner that the following relations are maintained:

When, in operation, the first speed is to be selected, the second clutch C is coupled and the first brake 8, applied. The ring gear R of the third planetary gear set 14 now rotates with the input shaft 10 and the pinion carrier 15 is held stationary, so that the following equations hold:

Ns Nr and Np 0.

In this condition, the sun gear S is rotated directly by the input shaft 10 with the pinion carrier 15 held stationary so that the ring gear R and the pinion carrier 16 of the planet pinion P rotate at a speed corresponding to a vector NN, in FIG. 1a. With the sun gear S rotating with the input shaft 10, the ring gear R and the sun gear 5;, rotate at a speed corresponding to a vector 00,. The ring gear R rotating with the input shaft and the sun gear S rotating at a speed corresponding to 0'0',, the pinion carrier 17 of the planet pinion P rotates at speed corresponding to LL providing a gear ratio for the first forward vehicle speed.

The gear ratio establishing the first speed thus delivered from the output shaft 11 is thus expressed as:

When the vehicle speed is to be shifted from the first to the second speed, then the first brake B, is released and instead the second brake B is applied with the second clutch C kept coupled. Thus:

With the brake B applied, the pinion carrier 16 is held stationary and the sun gear 8;, rotates with the input shaft 10 so that the ring gear R and the sun gear S are rotated at a speed corresponding to a vector 00' in FIG. 10. With the clutch C coupled, the ring gear 8;, rotates with the input shaft 10 so that the pinion carrier 17 of the planet pinion P rotates at a speed corresponding to a vector LL providing a gear ratio for the second forward speed.

The gear ratio for the second vehicle speed is thus expressed as:

NS1/Np3 1 (13/1 052113.

When the speed is to be shifted from the second to the third speed, the second brake B is released and instead the third brake 8;, applied with the second clutch C kept coupled. Thus:

Nl'g N83 O and Nra N52.

With the brake 8:, applied and the clutch C coupled, the sun gear 8;, is held stationary and the ring gear R rotates with the input shaft 10 so that the pinion carrier 17 of the planet pinion P rotates at a speed corresponding to a vector LL which provides a gear ratio to establish the third forward speed.

The gear ratio for the third speed is thus expressed as:

NS1/NC3 1 a3- When the speed is to be shifted from the third to the fourth speed, then the third brake B is released and the first clutch C coupled with the second clutch C kept coupled. Thus:

Nr Nr Ns With the brakes B B and B released and the clutches C and C coupled, all the planetary gear sets rotate with the input shaft so that the revolution speed of the pinion carrier 17 of the planet pinion P is equal to the speed of the input shaft, as indicated by a vector LL; in FIG. 1a.

The gear ratio for the fourth speed attained in this manner is thus expressed as:

In order to streamline the shifting between the first and second speeds, a one-way clutch 23 may be provided on the planet carrier 15 of the first planetary gear set 12, as illustrated in FIG. lb, if desired.

It will be appreciated that the gear train shown in FIGS. 1 and 1b are suited to provide ease of gear shifting operations because the gear ratios can be changed merely by releasing only one of the clutches and brakes and actuating another one of them.

FIG. 2 illustrates another form of the gear train according to the invention. The gear train is constructed so as to provide four forward and one reverse speeds with use of three identical planetary gear sets 12, 13 and 14 which are operated by two clutches C and C and three band brakes B B and B When the vehicle is to be moved backwardly, the first 5 l dutch (31 is coupled and the Second brake B2 applied The first clutch C is linked on the one hand with the Thus; input shaft 10 of the transmission and on the other with the ring gear R, of the first planetary gear set 12. The Nrz Nra and Npz second clutch C which is also linked with the input With the brake B applied and the sun gear S rotat- 4O shaft 10, is linked with both the sun gears S and S of ing with the input shaft 10, the ring gear R and the sun the first and second planetary gear sets 12 and 13, regear 8:, rotate at a speed corresponding to a vector spectively, through a drum 24 for the first band brake 00' Since, in this instance, the clutch C is coupled, B,. The sun gears S and S are as a result constantly the ring gear R also rotates at a speed equal to the connected together and rotatable with each other. The speed of the ring gear R and sun gear S Both the ring planet pinion P, of the first planetary gear set 12 is congear R and sun gear 8;, rotating at'the speed correstantly connected to and rotatable with the ring gear R sponding to 0'0' the planetary gear set 14 rotates in of the second planetarys gear set 13, sun gear 5; of the its entirety at this speed. The output shaft 11 is thus rothird planetary gear set 14, and output shaft 11 of the tated at a Speed Corresponding r in a direction P- transmission through the pinion carrier 15 and an interposite to the rotation of the input Shaft 1 mediate shaft 25. The planet pinion P of the second The gear ratio for the reverse speed thus established planetary gear set 13 is constantly connected to and rois thus expressed as: tatable with the planet pinion P of the third planetary NS IN 1 /a gear set 14 through the pinion carriers 16 and 17 which p3 form part of a drum 26 for the second band brake B The conditions of the clutches and brakes for the dif- The ring gear R of the third planetary gear set 14 is ferent vehicle speeds and the gear ratios attained under ted to a dr m 27 for the third band brake B Table II C C2 B B2 B Gear Ratios F lst 1+0: ct,/cr 2.45)

(1; 3rd 1 a, 1.45)

Rev. l/a (2.22)

The conditions of the clutches and the brakes for the different vehicle speeds and the gear ratios attained in these conditions are tabulated in Table II; the gear ratios are calculated in a manner similar to that discussed in connection with the gear train of FIG. 1.

When the first forward speed is selected, the clutch C, is coupled and the brake B applied. In this instance, the operations of the individual rotary members will be easily understood if it is assumed that'the output shaft 11 is first rotated to impart a rotational effort to the input shaft 10, conversely to the actual operation. Thus, if the output shaft 11 is rotated at a speed corresponding to a vector AA, in FIG. 2a, then the ring gear R, and the pinion carrier 15 of the planet pinion P, will rotate at the same speed as the output shaft 11. With the brake B applied, the planet pinion P is held stationary so that the sun gears S and S, rotate at a speed corresponding to a vector 0,. Such rotation of the sun gear S, and the pinion carrier I (which revolves at a speed equal to the revolution speed of the output shaft 11) will dictate the speed at which the ring gear R, of the first planetary gear set 12 rotates as represented by a vector 0'0, in FIG. 2a. The driving force is actually carried to the input shaft 10, not to the output shaft 11, so that the flow of rotation is exactly inverse from that discussed above. Thus, it is apparent that the first speed corresponds with the vector LL,, in FIG. 2a.

When the speed is shifted from the first to the second speed, then the brake B, is released and the brake B is applied with the clutch C, kept coupled. Here, it is also assumed that the driving force is initially transferred to the output shaft 11. If the output shaft 11 is rotated at a speed corresponding to a vector LL, in FIG. 2a, the sun gear 8,, rotates with the output shaft 11. The ring gear R being held stationary with the brake B applied, the pinion carriers 17 and 16 rotate at a speed corresponding to a vector MM,. Since, in this instance, the ring gear R rotates with the output shaft 1 1 at a speed corresponding to the vector LL the sun gears S, and S, rotate at a speed corresponding to the vector 00,. The planet pinion P, is rotated with the pinion carrier rotating with the output shaft 11 so that the ring gear R, will rotate at a speed corresponding to the vector 00, in FIG. 2a. The actual operations of the planetary gear sets are exactly converse from those discussed above but, anyway, it is apparent that the second speed corresponds to the vector LL, in FIG. 20.

When the speed is shifted from the second to the third speed, the brake B, in lieu of the brake B is now applied with the clutch C, kept coupled, so that the sun gears S, and S, are held stationary and the ring gear R, rotates with the input shaft 10. The pinion carrier 15 supporting the planet pinion P,, therefore, rotates at a speeds corresponding to a vector LL, providing a gear ratio for the third forward speed.

When the speed is further shifted up from the third to the fourth speeds, all the brakes are released and the clutches are coupled so that the first planetary gear set 12 rotates in its entirety at the same speed as the input shaft 10. The speed of the input shaft 10 is in this manner transferred to the output shaft 11 as it is.

For effecting the reverse movement of the vehicle,

the clutch C is coupled and the brake B applied. The sun gear 8, now rotates with the input shaft 10 with the pinion carrier 15 held stationary so that the ring gear R rotates at a speed corresponding to a vector LL, which provides a gear ratio to establish the reverse speed. i

It will now be appreciated that the gear train of FIG. 2 is, similarly to that of FIG. 1, adapted to provide ease of gear shifting operations because the gear ratios can be changed merely by releasing only one of the clutches and brakes and actuating another one of them.

FIG. 3 illustrates still another form of the gear train according to the invention constructed to provide four forward and one reverse speeds. The gear train also has three identical planetary gear sets 12, I3 and 14 with two clutches C, and C and three brakes B,, B and 8,, as shown.

The first clutch C, is linked on one side with the input shaft 10 and on the other with the ring gear R, of the first planetary gear set 12 through a drum 28 of the first band brake B,. The second clutch C is linked on one side with the input shaft 10 and on the other with the sun gears 5,, S and S of the first, second and third planetary gear sets 12, 13 and 14, respectively, through an intermediate shaft 29. The sun gears S,, S, and 8,, are thus constantly connected to each other and rotatable with the input shaft 10 when the clutch C, is coupled. The pinion carrier 15 of the planet pinion P, of the first planetary gear set 12 is constantly connected to and rotatable with the ring gear R of the second planetary gear set 13 through a drum 30 for the second band brake B The pinion carrier 16 of the planet pinion P of the second planetary gear set 13 is constantly connected to and rotatable with the ring gear R of the third planetary gear set 14 and is linked with the third brake B, through a drum 31. The pinion carrier 17 of the planet pinion P of the third planetary gear set 14 is connected to the output shaft 11. A one-way brake 32 is provided to prevent the pinion carrier 16 and ring gear R, from rotating in a direction opposite to the rotation of the input shaft 10.

In consideration of the constant connections between some of the rotary members of the planetary gear sets in this embodiment, the following relations hold:

Np Nr Np, Nr, and Ns, Ns, N5

The conditions of the clutches and brakes for the different vehicle speeds and the gear ratios attained in these conditions are tabulated in Table III. 

1. A gear train comprising:
 1. an input shaft (10);
 2. an output shaft (11);
 3. a first planetary gear set (12a) having a ring gear (R1), a pinion carrier (15a) carrying planet pinion (P1) meshing with the ring gear (R1) and a sun gear (S1) meshing with the planet pinion (P1), the pinion carrier (15a) thereof being connected to said output shaft;
 4. second planetary gear set (13a) having a ring gear (R2) and a planet pinion (P2) carried by the pinion carrier (15a) of said first planetary gear set (12a), said ring gear (R2) meshing with the planet pinion (P2) of said second planetary gear set, the planet pinion (P2) of said second planetary gear set meshing with the planet pinion (P1) of said first planetary gear set (12a);
 2. an output shaft (11);
 3. a first planetary gear set (12a) having a ring gear (R1), a pinion carrier (15a) carrying planet pinion (P1) meshing with the ring gear (R1) and a sun gear (S1) meshing with the planet pinion (P1), the pinion carrier (15a) thereof being connected to said output shaft;
 4. second planetary gear set (13a) having a ring gear (R2) and a planet pinion (P2) carried by the pinion carrier (15a) of said first planetary gear set (12a), said ring gear (R2) meshing with the planet pinion (P2) of said second planetary gear set, the planet pinion (P2) of said second planetary gear set meshing with the planet pinion (P1) of said first planetary gear set (12a);
 5. A third planetary gear set (14) having a ring gear (R3) connected to the pinion carrier (15a) of said first planetary gear set, a pinion carrier (17) carrying a planet pinion (P3) meshing with the ring gear (R3) thereof and a sun gear (S3) meshing with the planet pinion (P3) thereof, the sun gear (S3) thereof being connected to the sun gear (S1) of said first planetary gear set;
 5. A third planetary gear set (14) having a ring gear (R3) connected to the pinion carrier (15a) of said first planetary gear set, a pinion carrier (17) carrying a planet pinion (P3) meshing with the ring gear (R3) thereof and a sun gear (S3) meshing with the planet pinion (P3) thereof, the sun gear (S3) thereof being connected to the sun gear (S1) of said first planetary gear set;
 6. first clutch means (C1) for engaging said input shaft with the ring gear (R1) of said first planetary gear set during operation of first, second, third, and fourth forward speeds;
 7. second clutch means C2 for engaging said input shaft (10) with the sun gears (S1, S3) of said first and third planetary gear sets during fourth forward speed and reverse speed;
 8. first brake means (B1) for anchoring the sun gears (S1, S3) of said first and third planetary gear sets during third forward speed;
 9. second brake means (B2) for anchoring the ring gear (R2) of said second planetary gear set during second forward speed;
 10. third brake means (B3) for anchoring the pinion carrier (17) of said third planetary gear set during reverse speed; and
 11. one-way brake means (42(C3)) for preventing the pinion carrier (17) of said third planetary gear set from rotating in a direction opposite to the rotation of said input shaft (10).
 6. first clutch means (C1) for engaging said input shaft with the ring gear (R1) of said first planetary gear set during operation of first, second, third, and fourth forward speeds;
 7. second clutch means C2 for engaging said input shaft (10) with the sun gears (S1, S3) of said first and third planetary gear sets during fourth forward speed and reverse speed;
 8. first brake means (B1) for anchoring the sun gears (S1, S3) of said first and third planetary gear sets during third forward speed;
 9. second brake means (B2) for anchoring the ring gear (R2) of said second planetary gear set during second forward speed;
 10. third brake means (B3) for anchoring the pinion carrier (17) of said third planetary gear set during reverse speed; and
 11. one-way brake means (42(C3)) for preventing the pinion carrier (17) of said third planetary gear set from rotating in a direction opposite to the rotation of said input shaft (10). 